Two hands and a foot. That’s what it took to run a Marion 7400, the electric walking dragline Marion built from 1940 to 1974.
The company behind it was founded in Marion, Ohio, in 1884 as Marion Steam Shovel. Its steam shovels helped dig the Panama Canal, and it later built NASA’s two crawler-transporters for the Saturn V.
The 7400’s job was overburden, the earth and rock above what a mine or quarry is after. One unit worked a Pennsylvania limestone quarry with a 14-cubic-yard bucket.
PAmining’s video of a 1958 unit shows how that digging was done. One hand hoists the bucket, the other swings the machine, and the left foot lets out the drag cable.
The operator calls it a friction machine. Foot pedals work the drag and hoist brakes, and two DC motors swing it around. “I don’t mind running it at all,” the operator says.
One 7400 kept working in Sweden until 2008, 61 years after it arrived from Ohio.
Key facts
- Manufacturer: Marion Power Shovel Company, Marion, Ohio
- Built: 1940–1974
- Controls: friction, with foot-pedal drag and hoist brakes (1958 unit)
- Weight: about 600 tonnes (Swedish unit)
- Boom: 64 m (Swedish unit); 160 ft (1958 unit)
- Bucket: 14 yd³ (Pennsylvania unit); 6 m³ (Swedish units)
On PAmining, the video takes you inside a Marion 7400, from the motors to the cab.